The invention relates to a dynamoelectric machine comprising a stator and a rotor with a closed cooling circuit.
The cooling media used for cooling dynamoelectric machines are gases, in particular air and liquids. Combinations of these cooling principles are also provided in dynamoelectric machines in order to achieve efficient cooling
An electric machine is known from DE 299 13 314 U1 having a housing, with a stator and a rotor and water cooling, wherein the laminated core of the stator is shrunk into a housing and lies on the whole core length in the housing. A cooling spiral is provided between the inner jacket and outer jacket, wherein the air jacket provided radially outside represents a closed system.
The drawback of this that internal fans guide the internal circulating air flow onto the air jacket, which guides the internal air flow over cooling fins. The air jacket is then just as hot as the air emerging from the rotor. These hot regions present a large problem for maintenance staff in particular in confined spaces, e.g. in the gondolas of wind-power generators.
In addition, the heat emitted also heats the environment of the dynamoelectric machine. The cooling efficiency is also limited by a design of this kind since the part of the stator around which cooling water flows only accounts for a fraction of the overall length of the housing.